Some integrated circuits, such as driver circuits for power transistors, require bootstrap circuits to function most effectively. In one example, a bootstrap circuit comprises a capacitor and a diode and functions to provide voltage, stored in the capacitor, in addition to the supply voltage such that there is sufficient power to bias a transistor into linear operation. In another example, a bootstrap circuit comprises a capacitor and a transistor.
Bootstrap circuits typically are provided in addition to the package housing the power transistor or other integrated circuitry, though sometimes at least a portion of the bootstrap circuit is provided in the same package. For example, system-in-package configurations can comprise a bootstrap circuit module or similar configuration in which the bootstrap circuit is provided along with other modules in a single package, though the bootstrap circuit still remains at least partially distinct from the other modules within the package.
Complete integration of entire bootstrap circuits, however, remains a challenge, particularly with respect to true silicon-level integration of both a semiconductor-based bootstrap capacitor and the bootstrap diode, or a bootstrap transistor, with other circuit elements, such as power transistors and other devices. Challenges exist in further silicon-level integration of the bootstrap circuit elements with the power transistor or other circuitry to, e.g., save space and costs and provide simplified solutions, at least because of the range of bootstrap capacitances needed.